A satellite office is like a branch office or, to use an analogy from "The Office", like the Scranton branch of Dunder Mifflin is to the corporate office. In other words, its not really a virtual office because it physically exists. It's just an office in a different location where your company does business.

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So you can translate it literally: una oficina satélite. Or you can translate it less literally: una oficina sucursal/filial.